// 代码索引 3-3-6-1
#include <Eigen/Dense>
#include <iostream>
 
using Eigen::MatrixXf;
 
int main()
{
    MatrixXf m(2,2);
    MatrixXf n(2,2);
    MatrixXf result(2,2);
    
    m << 1,2,
         3,4;
    n << 5,6,
         7,8;
    
    result = (m.array() + 4).matrix() * m;
    std::cout << "-- Combination 1: --\n" << result << "\n\n";
    result = (m.array() * n.array()).matrix() * m;
    std::cout << "-- Combination 2: --\n" << result << "\n\n";
}